1. Field of the Invention
The present invention relates to an apparatus for measuring the color of a brilliant-cut diamond, and more particularly to such an apparatus for measuring the spectrum of a beam of light that has passed through a diamond, deriving tristimulus values X, Y and Z from the measured spectrum, and evaluating the color grade of the diamond.
2. Description of the Prior Art
Diamonds are normally evaluated by the qualities of "Four C's": color, clarity, cutting and carat weight. Color determination has heretofore been conducted by an organoleptic examination in which the hue of yellow is classified by human eyes into grades ranging from water-whiteness to light yellow for evaluation.
The organoleptic color determination however lacks objectivity no matter how skilled the observer may be. It frequently occurs in reality that a diamond color is differently judged by different observers. Proper determination of diamond colors is more desired since diamonds are getting more and more popular among people and their market is expanding. There has been a need for apparatus for properly measuring diamond colors without resorting to subjectified judgement by human observers.